Gaming machines, such as slot machines, video poker machines and the like, have been a cornerstone of the gaming industry for several years. In a typical reel-type slot machine, a payout of coin(s) or credit(s) is made to a player whenever certain combinations of symbols are displayed on the reels relative to a payline. To accommodate various players, each machine will accept a certain minimum wager amount per activation of the reels. For example, a player willing to bet larger amounts will chose a machine having $1.00 or $5.00 as its minimum wager amount instead of a $0.05 or $0.25 machine. Also, casino operators will adjust the total game payout percentage up or down based on the profitability that the operator of the gaming machine desires and whatever regulations are imposed upon the operator by the gaming authority that regulates the use of the gaming machine. Generally, the operator will set the payout percentage for each machine based on the minimum wager amount such that the payout percentages increase as the minimum wager amount increases. For example, the payout percentage of a $5.00 machine will be higher than the nickel machine.
Generally, the popularity of such gaming machines with players is dependent on the intrinsic entertainment value of the machine relative to other available gaming options and the likelihood (or perceived likelihood) of winning money at the machine. One concept which has been successfully employed to enhance the entertainment value of a game is the concept of a secondary or bonus game which may be played in conjunction with a basic game. The bonus game may comprise any type of game, either similar to or completely different from the basic game, which is entered upon the occurrence of a selected event or outcome of the basic game. The bonus game concept is the subject of U.S. patent application Ser. No. 08/835,840 [hereinafter "the '840 application"], filed Apr. 23, 1997, assigned to the assignee of the present invention and incorporated herein by reference. The '840 application discloses an embodiment wherein the basic game is a reel-type slot machine and the bonus game is a simulated reel-type slot machine implemented on a dot-matrix display. The bonus game is entered upon the appearance of a special symbol combination on the reels of the slot machine in the basic game. In the bonus game, the probability of winning combinations appearing on the reels, or the hit-rate, is much greater than that of the basic game. The player is permitted to keep playing and accumulating winnings from the bonus game until a losing trial occurs. Such a bonus game produces a significantly higher level of player excitement than the basic game because it provides a greater expectation of winning than the basic game and is accompanied by more attractive or unusual video displays and/or audio.
One feature in reel-type slot machines which has been successfully employed to enhance the perceived payoff value of a game is that of multiple paylines, scatter pay paylines or unusually-shaped paylines. Such games allow the player to select the number of paylines, vary the amount of credits (wager amount) bet on each line, and award regular payouts when winning combinations occur. These machines afford more opportunities to win with each activation of the reels. When placing bets on multiple paylines, the player increases his chances for a winning combination while at the same time betting more money.
While most players are likely to be attracted to the most entertaining and exciting of the machines, shrewd players will quickly recognize machines which present or will be perceived to present greater payoff opportunities relative to other available gaming options. Since a gaming machine with multiple paylines accepts a range of wager amounts from a minimum wager amount to a maximum wager amount, setting a machine to any one payout percentage would disadvantage a player betting a certain amount on a nickel machine relative to the same amount bet on a dollar machine which has a higher payout percentage. Some players will recognize the lower return and only play machines with the higher payout percentage. Also, other players unwilling to wager larger amounts associated with the machines having higher payout percentages will altogether turn away from playing the machines with lower payout percentages as well.
Since a greater payoff opportunity associated with a particular machine will attract frequent play and thereby produce greater revenues for the casino player, there is a need to develop new types of such games that will not discourage players from playing multiple coins or credits on any given machine. The present invention is directed to satisfying this need.